star Rob James-Collier has spoken about the show's current 'gay cure' storyline.
In recent episodes, fans of the ITV period drama have seen James Collier's character, Thomas Barrow, begin a painful process to try and change his sexuality.
Gay sex remained illegal in Britain in the 1920s, with men facing potential prison sentences if they were caught engaging in homosexual acts.
Speaking about Barrow's struggles, James-Collier said: "He wants to be able to love, so he embarks on quite a dark and serious journey rooted in his sexuality to try and change how he is.
"I really wanted to get down to why Thomas was how he is. For me, I made the choice it was his sexuality. You wake up every morning and your religion is telling you you’re condemned. I wouldn’t be surprised if a lot of men like Thomas did do this, because what was the alternative? There wasn’t one."
Meanwhile, the show's creator Julian Fellowes, said that Barrow's "fortitude" will "take him through a period of incredible physical discomfort".
"The result he seeks is impossible – it’s not to be obtained by any medical treatment, it was just quackery," he added.
's fifth series continues on Sunday (October 26) at 9pm on ITV.
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> ‘Downton’s Rob James Collier talks ‘harrowing’ gay storyline